Method and apparatus for mooring floating vessels

ABSTRACT

A method and apparatus for mooring floating vessels (e.g. ships) generally over a fixed location on the water bottom. The vessels are provided with guide means (e.g. a track) which encircle the hull of the vessel along a line which is spaced at or above the Plimsoll line and at or below the top edge of the hull. A plurality of movable carriages are carried by the guide means for separately attaching a plurality of anchor lines to the hull and for controlling the length thereof. Means are provided for selectively positioning the carriages at desired points along the track.

United States Patent 1191 Boschen, Jr.

[ METHOD AND APPARATUS FOR MOORING FLOATING VESSELS [76] Inventor: HenryC. Boschen, Jr., Rt. 4 Box 283, Chippewa Falls, Wis. 54729 [22] Filed:Oct. 10, 1972 [21] Appl. No.: 296,079

[52] U.S. C1. 114/206 R, 9/8 P, 114/0.5 D [51] Int. Cl B63b 21/50 8]Field of Search 114/206 R, .5 R, .5 F, 114/.5 D, 230, 231, 144 R, 144 B;9/8 P; 61/465 [56] References Cited UNITED STATES PATENTS 2,771,6171l/1956 Brack 9/8 P 3,191,201 6/1965 Richardson et a1 114/.5 D 3,461,8288/1969 Bielstein 114/230 3,538,880 11/1970 Smulders 9/8 P 1451 July 9,1974 Primary Examiner-Trygve M. Blix Assistant ExaminerCharles E.Frankfort Attorney, Agent, or Firm-Merchant, Gould, Smith & Edell [57]ABSTRACT A method and apparatus for mooring floating vessels (elg.ships) generally over a fixed location on the water bottom. The vesselsare provided with guide means (eg a track) which encircle the hull ofthe vessel along a line which is spaced at or above the Plimsoll lineand at or below the top edge of the hull. A plurality of movablecarriages are carried by the guide means for separately attaching aplurality of anchor lines to the hull and for controlling the lengththereof. Means are provided for selectively positioning the carriages atdesired points along the track.

6 Claims, 5 Drawing Figures PATENTEDJUL 91m 3.822.663

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. v iii-[6 I 3% H 1? XE? METHOD AND APPARATUS FOR MOORING FLOATINGVESSELS BACKGROUND OF THE INVENTION Often it is desired to moor a shipgenerally over a fixed location on the water bottom. This isparticularly true in off-shore well drilling operations and isespecially difficult to accomplish in deep water. Further, as winddirection and wind intensity change, it is often necessary or desirableto re-orient floating vessels to face into the wind or in some otherdesired direction while maintaining a position generally over the fixedlocation on the water bottom.

A variety of mooring methods and apparatus have been used and describedin the literature. Some methods involve elaborate schemes of positioninganchors and anchor lines. Another method involves the use of aircushioning devices and a circular superde'ck. Other methods envision theuse of a well which extends vertically through the vessel and throughwhich are passed a plurality of anchor lines.

The following patents illustrate various types of ship mooring methodsand apparatus.

Each system has its own advantages and disadvantages. For example, withsome prior art systems the method of use is so cumbersome as to beimpractical. Other systems are expensive and can be readily incorporatedinto ships and other vessels only during original construction.

There exists a continuing need for alternative methods and apparatus formooring vessels generally over a fixed position on the water bottom. Inparticular, there exists a need for a ship mooring method and relatedapparatus which can be used with and incorporated into existing vesselswithout major structural alteration or modifications.

SUMMARY: OF THE INVENTION The present invention involves a method andapparatus for mooring floating vessels (such as well drilling ships)generally above a fixed location on the water bottom. The vessel isprovided with guide means which substantially completely encircle thehull of the vessel along a line which is both at or above the Plimsollline and at or below the top edge of the hull. A plurality of attachingmeans are carried by the guide means for separately attaching aplurality of anchor lines to the hull. Control means are provided forselectively moving and positioning the attaching means along the guidemeans and for selectively accumulating or discharging anchor lines.

In a typical installation, a track is mounted on or in the hull of aship along a line near the top edge of the hull. A plurality ofcarriages are mounted on the track for movement fore or aft as desired.Controls (e. g. electrical, hydraulic, etc.) are provided to cause thecarriages to be moved fore or aft or to remain in the fixed position,all as desired. The carriages are further equipped with means forselectively accumulating or discharging anchor line.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of adrilling ship positioned over a fixed location on the water bottom.

FIG. 2 is a top view of the ship of FIG. 1 taken along the line 22 inthe direction of the arrows. A second orientation of the ship is shownin dotted lines.

FIG. 3 is an enlarged fragmentary cross sectional view of the presenttrack and carriage arrangement taken along the line 33 of FIG. 1.

FIG. 4 is an enlarged fragmentary sectional view of the track andcarriage taken along the line 4-4 of FIG. 3.

FIG. 5 is a cross sectional view of the track and carriage arrangementtaken along the line 55 of FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT THE VESSELS The presentmethod and apparatus can be used in conjunction with a variety ofvessels intended to be floated in a body of water. Thus, the inventionis applicable to ships, barges, semi-submersibles and the like. It isparticularly well suited for use with ships, especially well drillingships of the type used for off-shore oil and gas well drillingoperations.

GUIDE MEANS The vessels will be provided with means for supporting andguiding a plurality of anchor line attaching means about the perimeterof the hull to any selected point. The guide means will typically be inthe form of some type of track. A particularly convenient type of trackis a generally C-shaped channel within which can guide some means (e.g.wheeled carriages) for attaching anchor lines to the vessel. The trackwill be located along a line which is both at or above the Plimsoll lineof the vessel (i.e., at or above the water line) and at or below the topedge of the hull. Depending upon various design and otherconsiderations, the track can be located adjacent the top edge of thehull (e. g. along the perimeter of the main deck or at some pointbetween the top edge of the hull and the Plimsoll line). Locations at ornear the top edge of the hull are preferred so as to increase the rollstability of the vessel and to reduce exposure of the mooring apparatusto water. The track may be mounted external of the hull or can be formedwithin the hull.

For maximum versatility, the guide means (e.g. a channel track) shouldcompletely encircle the vessel. Such an arrangement will permit themeans for attaching anchor lines to the hull to be moved along the trackto any desired location around the hull. However, de-

sign considerations may make it desirable for the track to substantiallycompletely encircle the hull of the vessel without completely encirclingit (e.g. separate tracks may be mounted on each side of the hull frombow to stem with no track being provided across the bow or stem). Otherarrangements providing substantially complete encircling of the hullwill be suggested to those skilled in the art of ship construction andship mooring.

The following considerations are typically taken into account indetermining the type and location of the guide means of the presentinvention. First, the guide means should be mounted close to the hull ofthe ship (i.e. adjacent the perimeter of the hull) so they will notmaterially interfere with docking and other maneuver ing of the vessel.Alternatively means could be provided for moving the guide meansinwardly during docking and other operations. Secondly, the guide meanscan be mounted in a horizontal plane which passes through or close tothe center of floatation of the vessel or at some point above the centerof floatation at which the force exerted by the anchor lines acts toovercome the rolling effect of the waves. In this manner, rolling of thevessel is minimized when the moored vessel is struck by strong wavesallowing continuation of the drilling operation.

ANCHOR LINE ATTACHING MEANS A plurality of anchor line attaching meanswill be supported by and movable along the guide means. The purpose ofthe anchor line attaching means is for connecting a plurality of anchorlines to the hull. The attaching means include means for accumulatingand discharging anchor line on command. The attaching means may includeor be supplemented by means for storing excess anchor lines.

CONTROL MEANS Control means are provided for selectively positioning theanchor line attaching means at desired points along the guide means.Such controls can be mechanical, electric, hydraulic or the like. Aconvenient method for transmitting power to the anchor line attachingmeans is by use of a driven chain or cable which is moved in or alongthe guide means. If desired, a plurality of chains or cables can be used(eg. two parallel cables, each moving in a direction opposite that ofthe other). The anchor line attaching means can then be selectivelyconnected to one of the moving chains or cables (e.g. via a drive gearand clutch arrangement) to thereby alter the position of the attachingmeans. Similarly, the attaching means can be clamped to the guide meansor some other stationary object and the moving chain or cable can beused as a source of power to selectively accumulate or discharge anchorline (eg. by means of a winch). The movement of the attaching meansalong the guide means and the controlling of the length of the anchorlines can occur simultaneously if desired (as can the control of thelengths of several of the anchor lines).

DETAILED EMBODIMENT The present invention is further illustrated byreference to the following detailed description when read in conjunctionwith the drawings.

In FIG. 1 is shown a drilling ship generally designated by thenumeral 1. The ship includes a main deck 2, a hull 3 and a drillingtower 4. The ship includes a channel track 5 which completely encirclesthe ship along a line which is both above the Plimsoll line 6 and belowthe top edge of the hull 3. Within the generally C- shaped channel 5 aremounted a plurality of carriages 7.

As shown in FIG. 1, the ship 1 is equipped with four carriages 7 towhich are separately attached four anchor lines 8, 9, l0 and 11. A drillpipe 12 extends from the bottom of hull 3 of ship 1 and penetrates thebottom 13 of a body of water 14. An anchor buoy B is preferably attachedto one or more of the anchor lines 81 1.

As can be seen particularly well in FIG. 2, the carriages 7 are shiftedin channel track 5 to permit vessel 1 to be reoriented with regard towind or wave direction while maintaining a generally fixed locationabove a point on the floor of the body of water 141. For purposes ofcomparison, the four carriages 7 have been labeled A, B, C and D in thetwo superimposed views (which together form FIG. 2) to permit one toobserve how the positions of carriages 7 change in order to accommodatethe change in the position of ship 1. Note that anchor line attachingmeans 78 and 7C both shift to the opposite side of the ship when theship is reoriented over less than As shown in FIG. 2, a chain 15 alsoencircles the ship immediately adjacent channel track 5 to provide asource of power to the carriages 7. The chain 15 is driven by a motor 16through a transmission 17, a drive shaft 18 and sprocket 19. Other meansfor driving chain 15 (e.g. two or more sprockets and drive motors), aswell as the use of separate power sources mounted on each carriage 7,can also be utilized.

The details of construction of carriage 7 and related equipment are moreclearly shown in FIGS. 3, 4 and 5.

As shown in FIGS. 3-5, the carriage 7 comprises a carriage body 20 whichis supported within channel track 5 by rollers 2148. Carriage 7 includesa winch 29 for accumulating and discharging anchor line 30. Carriage 7further includes one or more gears 31 for engaging moving chain 15 andclutch means (not shown) provided for the purpose of either using thepower transferred to gear 31 via chain 15 to move carriage 7 withinchannel 5 or to transmit power from the gear 31 to winch 29.Alternatively, clutch means can be provided to selectively move gear 31into engagement within moving chain 15. Another gear 32 is provided forselectively engaging or disengaging fixed rack 33 which is mountedwithin channel 5 for locking carriage 7 in a fixed location withinchannel 5.

Gears 31 and 32 can be moved into or out of their respective operatingpositions by means of solenoids or other activating devices (not shown).For example, a remote control switch box 34 can be connected to eachcarriage body 20 by means of a plug in electrical cable. The switch boxcan be provided with switches for such functions as moving the carriage7 fore or aft, locking carriage 7 into position, and accumulating ordischarging anchor line 30 (e.g. by operating or disengaging winch drum29).

The details of construction of carriage 7 of FIG. 3 are more fully shownin FIGS. 4 and 5 where like numerals indicate like parts.

Electrical power can be transmitted to carriage 7 by various means suchas sliding contacts 35 as shown in FIGS. 4 and 5.

For most purposes, the method of the present invention will employ atleast three and preferably four anchor lines, each separately attachedto the ship. The ship or other vessel can be oriented or reoriented overa fixed location on the water bottom while or by moving the points ofattachment of the anchor lines along the guide path (e.g. along theguide track).

What is claimed is:

l. A vessel intended to be floated in a body of water,

said vessel comprising:

a. a hull;

b. guide means carried by said hull and substantially completelyencircling said hull along a line between the top of said hull and thePlimsoll line;

0. a plurality of attaching means moveably carried by said guide meansfor separately attaching a plurality of anchor lines to said hull andfor controlling the length thereof; and

d. control means operably connectable to said attaching means forselectively moving said attaching means to selected points along saidguide means to vary the position of the vessel, for holding saidattaching means at said selected points and for operating said attachingmeans to control the length of said anchor lines.

2. A vessel of claim 1 wherein said control means includes a chain-likemember which is mounted for movement adjacent said guide means and whichis op- 3. A vessel of claim 2 wherein said guide means is mounted justwithin said hull.

4. A vessel of claim 2 which includes at least four anchor lines.

5. A method of mooring a vessel in a body of water generally over afixed location on the water bottom. said method comprising:

a. attaching a plurality of anchor lines to the hull of said vessel atpoints which are located adjacent the perimeter of said hull along aline which is between the top edge of said hull and the Plimsoll line;

b. selectively moving the points of attachment of said anchor linesalong a pre-determined guide path which is fixed adjacent the perimeterof the hull to in turn move the vessel to orient the vessel in a desireddirection; and

c. holding the anchor lines at selected points along the guide path tohold the vessel oriented in said desired direction.

6. A method of claim 5 in which said anchor lines are each attached to adifferent carriage movably mounted on a track which extends around theperimeter of said hull for selective movement about said hull andincluding the step of adjusting the length of said anchor lines.

1. A vessel intended to be floated in a body of water, said vesselcomprising: a. a hull; b. guide means carried by said hull andsubstantially completely encircling said hull along a line between thetop of said hull and the Plimsoll line; c. a plurality of attachingmeans moveably carried by said guide means for separately attaching aplurality of anchor lines to said hull and for controlling the lengththereof; and d. control means operably connectable to said attachingmeans for selectively moving said attaching means to selected pointsalong said guide means to vary the position of the vessel, for holdingsaid attaching means at said selected points and for operating saidattaching means to control the length of said anchor lines.
 2. A vesselof claim 1 wherein said control means includes a chain-like member whichis mounted for movement adjacent said guide means and which is operablyconnectable to each of said attaching means in response to signals fromsaid control means.
 3. A vessel of claim 2 wherein said guide means ismounted just within said hull.
 4. A vessel of claim 2 which includes atleast four anchor lines.
 5. A method of mooring a vessel in a body ofwater generally over a fixed location on the water bottom, said methodcomprising: a. attaching a plurality of anchor lines to the hull of saidvessel at points which are located adjacent the perimeter of said hullalong a line which is between the top edge of said hull and the Plimsollline; b. selectively moving the points of attachment of said anchorlines along a pre-determined guide path which is fixed adjacent theperimeter of the hull to in turn move the vessel to orient the vessel ina desired direction; and c. holding the anchor lines at selected pointsalong the guide path to hold the vessel oriented in said desireddirection.
 6. A method of claim 5 in which said anchor lines are eachattached to a different carriagE movably mounted on a track whichextends around the perimeter of said hull for selective movement aboutsaid hull and including the step of adjusting the length of said anchorlines.